LED light intensity

wietefras

Well-Known Member
And we wonder why people talk trash about LEDs with company's advertising like that.
I know right. It's just despicable the way they try to fool people. And then when growers use those things they say "It's so powerful it's burning my plants". No it's not, it's just that all the light is bundled in the middle of your grow.

I used 1000W Gavita DE's myself. Amazing lights. Many manufacturers have started copying them since, but if you want to talk about "giant leaps", then perhaps that wasn't giant but at least Gavita really gave us a "leap".
 

wietefras

Well-Known Member
I have not been able to burn my plants with 100W LED strips so far. In late veg I was about 2 palm widths away with the strips.
I 'm at one palm width of height and plants are fine with that too. Some higher tops even half that.
 

giantsfan24

Well-Known Member
Fuck it I'm gonna say it and please no one don't take this personally this is a stupid fucking thread. No matter how smart any of us think we are, not one of us can give an exact answer. All these charts etc are a waste of time, they are based on an ideal space with no obstacles, eg do they have an 18inch canopy that is like a jungle, NO. Have any of them done a test with a defoliated canopy NO. I think the empty spaces are in our heads.
Grow some weed and be happy that you can actually grow.
RANT over, it's the weekend after all.
I know right?? I thought I just had a simple question, maybe a couple of pages of noob questions...
 

wietefras

Well-Known Member
That's good to know...practical info..always valuable.
Well it depends on the distance between the strips. If you have your strips 15cm apart then they can be about 10cm above the plants. If they are 30cm apart they will fina at about 20cm above the plants. Etcetera. It's a relative which pretty much works universally. If you have only one strip or board in the middle of a tent, then the "strip to strip distance" is equal to the width of the tent.

With strips I aim for 2/3 of the strip to strip distance as the height and let slightly higher tops get up to half the strip distance.

That's what those charts I posted actually are created to determine. Although then I usually calculate them as a PPFD matrix from the top, but in this case I ran a simulation for every cm distance and aggregated them in a light distribution over height chart.
 

Slinging PAR

Well-Known Member
Well it depends on the distance between the strips. If you have your strips 15cm apart then they can be about 10cm above the plants. If they are 30cm apart they will fina at about 20cm above the plants. Etcetera. It's a relative which pretty much works universally. If you have only one strip or board in the middle of a tent, then the "strip to strip distance" is equal to the width of the tent.

With strips I aim for 2/3 of the strip to strip distance as the height and let slightly higher tops get up to half the strip distance.

That's what those charts I posted actually are created to determine. Although then I usually calculate them as a PPFD matrix from the top, but in this case I ran a simulation for every cm distance and aggregated them in a light distribution over height chart.
So you claim. Where are the results?

Hard to take anything you post seriously because you don't understand the fundamentals.
 

churchhaze

Well-Known Member
Why bother with LEDs at all if you're going to use cfl or T5 to veg?

Veg is the low hanging fruit due to how long the lamps are on per day.

This thought process behind using fluoros for veg while using LEDs for flowering is asshat backwards. A better way to save power with less up front investment would be keep HPS in your flowering room and upgrading veg to LED first.
 
Last edited:

giantsfan24

Well-Known Member
Well it depends on the distance between the strips. If you have your strips 15cm apart then they can be about 10cm above the plants. If they are 30cm apart they will fina at about 20cm above the plants. Etcetera. It's a relative which pretty much works universally. If you have only one strip or board in the middle of a tent, then the "strip to strip distance" is equal to the width of the tent.

With strips I aim for 2/3 of the strip to strip distance as the height and let slightly higher tops get up to half the strip distance.

That's what those charts I posted actually are created to determine. Although then I usually calculate them as a PPFD matrix from the top, but in this case I ran a simulation for every cm distance and aggregated them in a light distribution over height chart.
Dude so you go from palm widths to cm?? "I'm just a country doctor Jim!" Lol thanks for splainin it
 
Last edited:

wietefras

Well-Known Member
How about just measuring with a ruler and leaving the guesswork out of the equation. That is how intelligent people do it.
I know you are just here to be annoying I'll give you one more actual answer. ANC brought up "2 palms width". Which actually makes a lot of sense since those are the perfect size to measure the needed distance. If you don't have a ruler at hand. There is no need to be that accurate anyway. It's not an exact science.

Personally I hang some sensors on the frame spaced around the height I like to maintain. No need for rulers or palms, but whatever floats people's boats.
 

Slinging PAR

Well-Known Member
I know you are just here to be annoying I'll give you one more actual answer. ANC brought up "2 palms width". Which actually makes a lot of sense since those are the perfect size to measure the needed distance. If you don't have a ruler at hand. There is no need to be that accurate anyway. It's not an exact science.

Personally I hang some sensors on the frame spaced around the height I like to maintain. No need for rulers or palms, but whatever floats people's boats.

Let us know when someone has taught you how to use a ruler. END.
 

wietefras

Well-Known Member
Let us know when someone has taught you how to use a ruler. END.
Let us know when you are able to use any form of physics properly. Understand par vs lumen, understand when a relation is inverse quadratic or linear, when you can calculate an average, when you have finally built a proper light fixture, when you have actually grown a plant. Or in your case just anything even remotely useful would be a step up.

Just stop trolling and finally do something useful with your life.
 
Last edited:

churchhaze

Well-Known Member
I just calculate my total power of PAR and divide by the area to find average intensity. A quick and dirty law of sines is all that's needed to make sure my lights overlap "enough" and there won't be appreciable dark spots. (rule of palm). We're talking about light distribution over a garden here.

When buying a light, people should really worry less about intensity and should focus more on total power output. Intensity in terms of lamps is just a trick to make a lamp seem better than it really is.

The way to increase light intensity as a user should be to increase/decrease footprint area. Want higher intensity? Smaller footprint. Want lower intensity? Bigger footprint. I can't be arsed to find instantaneous intensity, and it really doesn't matter in terms of yield.
 
Last edited:

Slinging PAR

Well-Known Member
Let us know when you are able to use any form of physics properly. Understand par vs lumen, understand when a relation is inverse quadratic or linear, when you can calculate an average, when you have finally built a proper light fixture, when you have actually grown a plant. Or in your case just anything even remotely useful would be a step up.

Just stop trolling and finally do something useful with your life.

Let us know once you have accomplished your task list. END.
 
Top